Treatment of keratinous fibers



United States Patent 3,144,300 TREATMENT OF KERATINOUS FIBERS Jean-Claude Cosnard, Juvisy-sur-Orge, and Claude 'Irzain, Bourg-la-Reine, France, assignors to Compagnie de Saint-Gobain, Neuilly-sur-Seine, France No Drawing. Filed Nov. 15, 1961, Ser. No. 152,641

Claims priority, application France Dec. 1, 1960 4 Claims. (Cl. 8127.6)

This invention relates to the process of treating kerati nous fibers, particularly wool, to make them resistant to felting and to shrinking. Felting and shrinking are related phenomena, the former relating to packing and adhesion of the fibers and the latter to shortening, usually by the action of water. The present invention is related to the minimization of both phenomena.

It has already been suggested that wool be treated with an aqueous acid solution of N-chlorinated-l-3-5-triazine in order to make it resistant to felting and N-dichloroisocyanuric acid has been successfully employed, conferring upon the wool or other keratinous fiber, a 'substantial resistance to both shrinking and felting. Nevertheless, that process has material disadvantages among which are the insolubility of the compound in water, the substantial loss of active chlorine during the dissolving of the isocyanuric acid and expressly the loss of active chlorine by retention in the bath. In the latter cases the loss of active chlorine may exceed -It is an object of the invention to treat wool and other keratinous fibers so as to improve their resistance to shrinking and felting beyond what was possible with prior art treatments of the type described. Another object is to prepare treating solutions of easier solubility which will more readily yield up their active chlorine. Another object is to avoid the loss of chlorine during the preparation of the solutions and their use.

The objects of the invention are accomplished generally speaking by treating wool or other keratinous materials in an aqueous solution of alkali metal dichloroisocyanurate in acid solution, following which excessive chlorine can be removed and the material washed and dried. The process of this invention produces better results than those which were obtainable by chlorinated isocyanuric acid. The compounds which are useful in the present invention have the following formula:

in which M is an alkali metal and Hal is a halogen which is preferably chlorine. The pH of the solution is advantageously about 2.

We have established the fact that the salts of alkali metals of dichloroisocyanuric acid, conversely to free acid, are easily soluble in water, dissolving them in acid media does not result in any active loss of chlorine, and the resulting solutions can be Wholly exhausted of active chlorine, which was not possible with prior art solutions all of which retained substantial quantities of it.

The textile materials and fibers treated by the present invention are given a superior resistance to felting and to shrinkage without attack on the fibers and without substantial change in color.

The aqueous solutions employed are advantageously of such concentration that the quantity of active chlorine present, expressed as a percentage of the weight of wool, is between 1 and 3%. The bath can be acidified with militia Elli-i ELM-Mitre...

either organic or inorganic acids among which formic acid is particularly satisfactory. These solutions may be used directly without any other addition for the treatment of keratinous textiles and notably for the treatment of articles such as raw wool, combed or carded skeins, yarn, woven fabrics, knitted goods and finished articles such as blankets and clothing.

The following examples are illustrative of the invention and do not limit the generality of what is elsewhere herein stated.

The tests have been carried out on strands of combed wool Nm/4/2/28, merinos quality, degreased and nondyed.

To evaluate the shrinking resistance of the various samples, squares of 15 x 15 cm. were knitted from these strands. Similar squares were knitted from nontreated wool. On these knitted samples, squares of 9 x 9 were outlined. After treatment of half the squares all were washed under rigorously identical conditions, and then the dimensions of the treated squares were compared with those of non-treated samples. The shrinking resistance is represented by the percentage of shrinking expressed in terms of the difference in area outlined on the samples treated and non-treated, when corrected to an area equal to which corresponds to a square 9 x 9. The washing periods were generally lengthened by in crements of a half hour or an hour at the temperature of 40 C. in a washing machine containing a laundry solution made of:

Soap of Marseille g 5 Anhydrous sodium carbonate g 0.5

Water liters l W001 fabrics as defined above were treated for 30 minutes at room temperature with acid solutions (pH 2) containing 1.5% of active chlorine based on the weight of the fabric. One of these solutions contained dichloroisocyanuric acid and the other contained the sodium salt of the acid acidified by formic acid to pH 2. The weight of the textile material to the weight of the bath was as 1 to 30. After treatment the test squares and identical squares which had not been treated were subjected to dechlorination with 3% sodium bisulfite solution of 36 B. The following table gives the results obtained by washing the two groups of samples in the solution from 30 minutes to 3 hours, the size of the squares being compared with those prior to treatment to determine the percentage of shrinkage. The percentage of shrinkage is an adequate reflection of the felting.

Table I Shrinking percentage after washing periods of- Treatment by- The above results indicate the technical advantage which the use of solutions made from the alkali metals salts of dichloroisocyanuric acid present over those made from the corresponding free acid.

ilvv- EXAMPLE 2 Table II Shrinking percentage after washing periods of Treatment by- 30 min. 1 hr. 2 hr. 3 hr.

Non-treated reference sample.

Solution of sodium diehloroisocyanurate Solutions of diehloroisocyanuric acid at 1.65% active chlorine As in the experiments described in Example 1, one notices the advantage which the solutions of sodium dichloroisocyanurate offer when compared to solutions prepared from the corresponding free acid. This advantage becomes especially noticeable in the longer washing periods.

It will be observed that the shrinking after three hours washing in Example 1 was reduced by about /3 and the shrinking after three hourswashing in Example 2 was reduced by about /2 compared to the results obtained using the dichloroisocyanuric acid of the prior art.

Any of the alkali metals may replace sodium in the compound and any of the halogens may replace chlorine, but such substitutions involve greater expense and are not recommended for that reason.

The pH of the treating solution is preferably around 2 but that is an optimum and solutions of either greater or lesser acidity may be used, sometimes with a falling off of efficiency as the acidity becomes increasingly remote from this optimum. The active chlorine content is preferably between 1 and 3% by weight of the fibers being treated, but this is an optimum which may be varied according to the material being treated or to affect the time of treatment. The optimum time of treatment is about 30 minutes which, in combination with the usual home or commercial washing period of 30 minutes, produced in Table I the amazing result of no shrinkage and in Table II a mere 1.2%.

The anti-shrinking treatment is completed by removing the free chlorine by means of known reagents such as sodium bisulfite.

The goods treated by the new process are superior and retain their ability to resist shrinkage and felting longer than the goods treated by the identified prior art.

The fibers can be bleached with ordinary bleaching agents such as H 0 Another advantage of the invention is in comparison to the acid of the prior art, which was of necessity first dissolved in an alkaline solution, either with sodium carbonate or tetrasodium pyrophosphate, after which it was again acidified. That process is eliminated by reason of the ready solubility of the new reagent.

As many apparently widely different embodiments of the present invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments.

What is claimed is:

1. A method of preventing the felting and shrinking of keratinous fibers which comprises degreasing the fibers, immersing them in an aqueous acid solution of sodium N-N dichloro-135 isocyanurate having a pH of about 2, and washing and drying the treated fibers.

2. The process of claim 1 in which the weight of active chlorine in the bath is about 1.5% of the weight of the fibers treated.

3. The method of claim 1 in which the temperature of treatment is about room temperature and the treatment is for a time between a few minutes and several hours.

4. A method of treating keratinous material to prevent shrinking and felting which comprises forming an aqueous solution of sodium dichloroisocyanurate containing about 1.5% of active chlorine, adding formic acid to the solution to bring it to a pH about 23, immersing the material in such solution, removing and dechlorinating the material in about 3% sodium bisulfite solution of about 36 B., and rinsing and drying the material.

References Cited in the file of this patent UNITED STATES PATENTS 2,913,460 Brown Nov. 17, 1959 2,993,747 Scott July 25, 1961 FOREIGN PATENTS 219,930 Australia Jan. 22, 1959 

1. A METHOD OF PREVENTING THE FELTING AND SHRINKING OF KERATINOUS FIBERS WHICH COMPRISES DEGREASING THE FIBERS, IMMERSING THEM IN AN AQUEOUS ACID SOLUTION OF SODIUM N-N DICHLORO-1-3-5 ISOCYANURATE HAVING A PH OF ABOUT 2, AND WASHING AND DRYING THE TREATED FIBERS. 